: [core] Implement inspect and inspect_str on the Sub PMC, making various bits of information about the arguments it takes available. Re-implement arity in terms of inspect_str. As a bonus, the data is now cached, so it'll perform better.

any C programmers here? Trying to figure out t/codingstd/c_parens.t; I've fixed most of the errors, but test one is failing in packfile.h, near "INTVAL (" ... which looks fine, according to the spec. Any clue?